In a nuclear Pressurized Water Reactor (PWR), the power level of the reactor is controlled by inserting and retracting control rods, which may include shutdown rods, in a reactor core.
Current designs of many nuclear power plants are equipped with control and shutdown rods which are inserted and withdrawn from the reactor core to control the reactivity by absorbing neutrons. Specifically, in Pressurized Water Reactors (PWRs), the movement of each rod is facilitated by its own electromechanical magnetic jack mechanism located atop the reactor vessel. Two examples of rod control systems that operate on this principle are the Control Rod Drive Mechanism (CRDM) and Control Element Drive Mechanism (CEDM). Both of these mechanisms consist of a set of coils that provide precise vertical movement to the rod by sequentially inducing a magnetic field in the coils to operate the mechanical parts of the system. The magnetic flux provides the energy needed to hold, insert, or withdraw the rod from the reactor core.
Thus, systems and methods to verify proper rod movement and to diagnose developing problems with the rod control systems would be valuable in maintaining proper and safe operation of nuclear plants.